Composite decking system

ABSTRACT

A composite deck assembly includes a baseplate and a top plate secured to the baseplate. The baseplate is formed from a first composite matrix comprising strands of reinforcing fibers oriented in first direction and a polymer resin. The baseplate includes a plurality of ribs and a plurality of laterally extending open channels disposed between the ribs. The top plate is formed from a second composite matrix of reinforcing fibers in a polymer resin, and is secured, optionally releasably, to the baseplate so as to generally enclose at least a portion of the channels. All the reinforcing fibers in the baseplate may be limited to being either the strands oriented in the first direction or matted reinforcing fibers having a random orientation. At least one of the base section and the top plate may be translucent. The open channel configuration simplifies manufacture and lowers cost.

BACKGROUND OF THE INVENTION

The present invention is directed to a structural assembly, formedprimarily from composite matrix materials having reinforcing fibers in apolymer matrix, which may be used as a decking system or for otherapplications.

The need for alternative materials and configurations for load bearingdecks has long been recognized. Conventional load bearing decks, such asfor vehicular bridges, have historically been made from steel andconcrete. While the construction techniques, and materials employed,have evolved over time for steel and/or concrete bridges, theconstruction process has proved to be very labor intensive, and theresulting structures have proven susceptible to corrosion and otherdegradations.

Partially in response to these cost and degradation issues, it has beenproposed to use decking systems based on polymer composite matrixmaterials rather than steel and/or concrete. For instance, U.S. Pat. No.5,794,402, incorporated herein by reference, proposes using a modularstructural section formed from a polymer composite matrix to formsandwich-type load bearing deck panels for bridges. The '402 patentproposes using a plurality of polymer composite matrix core memberssandwiched between upper and lower facesheets to form modular sandwichpanels. The core members are described as hollow tubes, typically with atrapezoid cross-section. While the patent indicates that the tube may bemade using a pultrusion process, the actual fabrication of such tubesusing pultrusion has proven difficult, primarily because pultrusion ofhollow tubes, with a fully enclosed passage, is technologicallydifficult. In simple terms, pultrusion of such hollow shapes requiresthe use of floating dies, which are difficult to control duringmanufacture. In addition, the patent teaches that layers of reinforcingfibers with so-called 45°-45°-90° orientation should be used; however,use of such 45°-45°-90° orientation layers is very expensive. Thus,while the modular and polymer composite matrix approach of the U.S. Pat.No. 5,974,402 has some theoretical advantages over traditional steeland/or concrete approaches, it has proved difficult to manufacture.

Accordingly, there remains a need for alternate composite structuralassemblies that are easier and/or less costly to make and use. Ideally,such an assembly should be capable of being used for applications otherthan a load bearing deck, but this is not strictly required.

SUMMARY OF THE INVENTION

A composite structural assembly of the present invention includes abaseplate having a plurality of laterally extending open channels and atop plate secured to the baseplate. The baseplate is formed from a firstcomposite matrix comprising reinforcing fibers and a polymer resin, andincludes a generally planar base section having first and second sides,a plurality of ribs extending from the first side of the base section,and the plurality of open channels disposed between the ribs andgenerally bounded by the adjacent ribs and the first side of the basesection. In some embodiments, the ribs have a generally T-shapedcross-section and may have laterally extending cap sections disposeddistal from and generally parallel to the first side of the basesection. The top plate is formed from a second composite matrix ofreinforcing fibers and a polymer resin, and is secured to the baseplateso as to generally enclose the channels. Preferably, the top plate isremovably secured to the baseplate. Further, in some embodiments, atleast one of the base section and the top plate are translucent.

The first composite matrix of the baseplate may include a plurality offirst strands of reinforcing fibers, with the first strands oriented ina first direction generally parallel to the channels. The secondcomposite matrix of the top plate may include a plurality of secondstrands of reinforcing fibers, with the second strands orientedgenerally perpendicular to the first strands. Either, or both, the firstand second composite matrixes may optionally include a plurality oflayers of matted reinforcing fibers having a random orientation. Inpreferred embodiments, substantially all the reinforcing fibers in thefirst composite matrix are either the strands oriented in the firstdirection or the matted reinforcing fibers having a random orientation.

The open channel configuration of the baseplate of the present inventionallows for easy access within the channels of the base section, andtherefore the sides of the ribs, thereby simplifying manufacture. Inaddition, the use of singly oriented strands of reinforcing fibers(optionally with the matted layers of random orientation) allows formuch lower cost materials to be used.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a perspective view of one embodiment of the compositestructural assembly of the present invention.

FIG. 2 shows a side view of a baseplate shown in FIG. 1.

FIG. 3 shows a more detailed view of a portion of the baseplate shown inFIG. 2.

FIG. 4 shows a partially exploded side view of the composite deckingsystem of FIG. 1 employed in a bridge application.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

One embodiment of a composite structural assembly of the presentinvention is shown in FIG. 1, and generally indicated at 20. Theassembly 20 includes a baseplate 30 and a top plate 80 secured to thebaseplate 30. As shown in more detail in FIGS. 2-3, the baseplate 30includes a base section 40, a plurality of ribs 50, and a plurality ofchannels 60. The base section 40 may be a generally flat, preferablyrectangular, member with a top side 42 and a bottom side 44. The ribs 50extend up from the top side 42 of the base section 40 and mayadvantageously be of a generally T-shaped configuration with a columnsection 52 and a cap section 54. The column section 52 extends generallyperpendicularly away from the base section 40 and may have a generallyrectangular cross-section, or tapered as desired. The joint between thecolumn section 52 and the top side 42 of the base section 40 may beconfigured to reduce stresses and/or to simplify manufacturing, such asby being appropriately radiused. The cap section 54 is formed on the endof the rib 50 opposite the joint with the base section 40 such that thecap section 54 is spaced from the base section 40. The cap section 54may advantageously take the form of a generally flat element disposedgenerally perpendicular to the column section 52 of the rib 50 andgenerally parallel to the base section 40 of the baseplate 30. Again,the joint between the column section 52 and the cap section 54 may bepreferably configured to reduce stresses and/or to simplifymanufacturing, such as by being appropriately radiused as shown. The capsections 54 may include a plurality of holes 56 on their top sides foraccepting fasteners (see FIG. 4), as discussed further below. The ribs50 are preferably spaced from one another a uniform distance, with theend ribs 50 being spaced a half-spacing from the respective ends of thebaseplate 30.

Between each pair of adjacent ribs 50 is a laterally extending openspace referred to herein as a channel 60. When viewed endwise, thesechannels 60 may be conceptually divided into two sections, a cavity 62and a gap section 64. The cavity 62 is disposed closest to the basesection 40, and is generally defined by the walls of the adjacent ribs50 and the intervening portion of the top side 42 of the base section40. The gap sections 64 are the areas between the distal end portions ofthe ribs 50 and connect their respective cavities 62 to the area abovethe ribs 50. Like the ribs 50, the channels 60 advantageously runlaterally from one edge of the baseplate 30 to the opposite edge.

The top plate 80 may take the form of a generally flat rectangularmember of relatively thin thickness when compared with the height of thebaseplate 30. The top plate 80 may advantageously include a plurality ofcounter-sunk screw holes 82 aligned in rows to correspond with thedistal ends (e.g., cap sections 54) of the ribs 50 of the baseplate 30.The top plates 80 may have peripheral edges that are generallyperpendicular to their main faces; however, one or more of theperipheral edges of the top plates 80 may alternatively be angled tocreate an overlapping joint when top plates 80 are abutted.

When the top plate 80 is secured to the baseplate 30, the top plate 80bridges the gap sections 64, thereby enclosing the channels 60 in thebaseplate 30. Thus, the combination of the baseplate 30 and the topplate 80 may form a modular panel section with what may be referred toas a “sandwich” construction, with the top plate 80 and the base section40 forming generally parallel surfaces, and the ribs 50 extendingtherebetween.

The main body of the baseplate 30 and the top plate 80 are formed from acomposite matrix that includes reinforcing fibers in a polymer resin.For information about the reinforcing fibers and polymer resin matrix,attention is directed to U.S. Pat. No. 5,794,402. In the baseplate 30,the composite matrix is formed from a plurality of strands 100 ofreinforcing fibers that are disposed so as to be generally parallel withthe channels 60. Thus, in FIGS. 2-3, only the ends of the strands 100are shown. The resin 120 forming the matrix surrounds the strands 100.In addition, in order to simplify the manufacturing process, there maybe a layer of reinforcing fiber “mat” 102 between each layer of strands100, or between each second layer of strands 100, or each third layer ofstrands 100, etc. The mat 102 consists of reinforcing fibers of the sameor a different type that are randomly oriented rather than oriented inone, or only a few select, directions.

Likewise, the polymer composite matrix of the top plate 80 is formedfrom a plurality of reinforcing fiber strands 110 in a resin matrix,with optional layers of “mat” 112.

The baseplate 30 and the top plate 80 may be formed by a process knownin the art as pultrusion. In somewhat over-simplified terms, thepultrusion process involves the pulling of a plurality of strands (e.g.,strands 100 or strands 110) through a shaping die where resin is added.The resulting product has a cross-sectional shape corresponding to thedie. For the present invention, the baseplate 30 may be formed bypultrusion in the direction of the channels 60, so that the strands 100are aligned in the direction of pultrusion. The strands 100 in thebaseplates 30 may be evenly distributed therein. However, it may beadvantageous to have a non-uniform distribution of strands 100 withinthe baseplate 30. For instance, it may be advantageous to have thedensity of strands 100 vary as a function of distance from the neutralaxis of the baseplate 30, as the strands 100 nearest the neutral axis donot add significantly to the bending strength of the baseplate 30, butdo add cost. Thus, the column section 52 of the rib 50 may have a lowerdensity of strands 100 than the base section 40 and the cap section 54.

The top plate 80 may also be formed by pultrusion. For the top plate,the direction of the strands 110 should also be in the direction ofpultrusion. Note however, that strands 100 and strands 110 willultimately be disposed in perpendicular orientations with respect toeach other in most embodiments of the present invention, as describedfurther below.

While pultrusion has been proposed before for bridge decking components,for instance in U.S. Pat. No. 5,794,402, the cross-sectional shapesemployed have proved to be difficult to make. This is due to the fullyenclosed nature of the proposed cross-sectional shapes. For instance,the “tubes 46” of FIG. 3 in the '402 patent have central passages thatare fully enclosed by the surrounding walls. Such fully enclosedcross-sections are difficult to manufacture, particularly using apultrusion method. In sharp contrast, the open channel configuration ofthe baseplate 30 of the present invention allows for easy access to thetop side 42 of the base section 40, thereby simplifying manufacture.

By way of illustrative example, the assembly 20 of the present inventionmay be employed as part of a vehicular traffic bridge. Variousstructural supports of a bridge, such as pillars and beams 12, areinstalled using any conventional approach. Referring to FIG. 4, therelevant beams 12 in this example are oriented in the traffic flow (orlongitudinal) direction 18. The assembly 20 described above may then beinstalled over the beams 12, with each baseplate 30 and top plate 80preferably on the order of four feet by fifty feet, or more preferablyeight feet by fifty feet. Before installing the structural assembly 20,the top of the relevant beams 12 are preferably prepared with L-shapedclips (not shown) added to the edges of the beams 12 and optionallycaulked on their upper surfaces. The space between the L-shaped clipsand the top of the beam is eventually filled with grout 14, with theweight of the decking system bearing on the beams through the grout 14when the grout 14 has set. This approach to preparing the beams 12 iscommonly referred to in the industry as “variable haunch,” and is wellunderstood by those of ordinary skill in the art.

Thereafter, the baseplate(s) 30 are affixed to the beams 12 by any knownmethod. For instance, each baseplate 30 may have suitable holes drilledor otherwise formed therein at suitable intervals for so-called Nelsonstuds 16 to be installed into the beams 12. If used, the top of eachNelson stud 16 should extend up through the hole and into thecorresponding cavity 62 of the baseplate 30. Grout 14 is then pumped into fill the cavity 62 around the Nelson stud 16. Preferably, somenon-load bearing dividers are added inside the channels 60 on eitherside of each Nelson stud 16 so that the grout 16 surrounding the Nelsonstud 16 forms a small grout pocket, and does not fill the entire channel60. In addition, the grout 14 flows downward around the Nelson stud 16and into the space between the baseplate 30 and the beam 12. It shouldbe noted that induced vibration of the structure may advantageously beused to aid in the flow of the grout 14 so that the grout completelyfills the space between the baseplate 30 and the beam 12. The adjoiningbaseplate 30 is then likewise installed, and so forth. The adjoiningbaseplates 30 are joined together, such as by using connecting plates 34secured in place by suitable fasteners 36 seated in corresponding tappedholes in the edges of the baseplates 30. While not shown, the connectingplates 34 may, if desired, rest in corresponding recesses formed alongthe edges of the baseplates 30. At this point, the baseplates 30 arejoined together and secured to the beams 12. The top plates 80 are thensecured to the baseplates 30, with the reinforcing strands 110 of thetop plates 80 oriented in the direction 18 of traffic flow andperpendicular to the strands 100 in the baseplates 30. The top plates 80may be glued to the cap sections 54 of the ribs 50, but are preferablyremovably secured thereto by suitably spaced bolts. It may beadvantageous to seal and/or install expansion joints between adjacenttop plates 80 using any known technique. Finally, an additional layer ofwear surface may then be applied over the top plates 80, if desired.Note that it may also be advantageous to apply some or all of theadditional wear surface to the top plates 80 during manufacture, priorto transporting the same to the installation site.

For the installation approach discussed above, it has been assumed thatthere is a one-to-one correlation between the number and size (area) ofbaseplates 30 and top plates 80, with the two components aligned withone another to form a sandwich panel. Within such a panel, the longdimension of the baseplate 30 (e.g., fifty feet) is in the samedirection as the long dimension of the top plate 80 (e.g., fifty feet),but strands 100 and strands 110 are oriented perpendicular to oneanother. However, the present invention should also be construed tocover arrangements where a given top plate 80 is secured to a pluralityof baseplates 30, thereby enclosing channels 60 from more than onebaseplate 30. In addition, some embodiments of the present invention mayhave the long dimension of the baseplates 30 running in one direction(e.g., transverse to traffic flow 18) and the long dimension of the topplates 80 running in a perpendicular direction (e.g., parallel totraffic flow 18). Whatever the orientations of the baseplate 30 and thetop plate 80, strands 100 and strands 110 should be oriented generallyperpendicular to one another once installed.

In addition to bridge installations, the present invention isparticularly suited to parking deck applications. The installation inparking decks may be carried out substantially as described above. Inaddition, the channels 60 may be used to house cables, conduits,utilities, heating elements, drains, and the like, particularly thosechannels 60 not used for Nelson studs 12. Indeed, if the matrix of thebaseplate 30 and/or the top plate 80 is translucent, then lightingelements may be installed in the unused channels 60. Further, for theembodiments where the top plate 80 is removably secured to thebaseplate(s) 30, the relevant top plate 80 may be removed to provideaccess to the lighting, cabling, etc. for repair or replacement, andthereafter re-secured in place.

Of course, the structural assembly 20 of the present invention is notlimited to bridge or parking deck applications, and may also be used forany applications where a load bearing panel is required or desired(e.g., in offshore oil platforms, floating platforms, etc.). Further,the structural assembly 20 may also be used in non-horizontalapplications, such as vertical walls for buildings, noise walls, floodwalls, and the like, where the structural assembly 20 is notsubstantially loaded.

By way of non-limiting example, a useful composite deck assembly 20 maybe made with a baseplate 30 four feet wide by fifty feet long having abase section 40 of ½ inch thickness, three ribs 50 of seven inch heightand spaced at one foot intervals, approximately ½ inch wide rib columns52, and four inch wide cap sections 54. The base section 40 of thebaseplate 30 may be made in an alternating layered fashion with fourlayers of strands 100 of sixty-four yield (a measure of length per unitweight of the reinforcing strand) E-glass at a density of eight strands100 per inch, and five layers of E-glass mat 102, both in an isophthalicpolyester resin 120. The column section 52 of the ribs 50 of thebaseplate 30 may likewise be made in alternating layered fashion withthree layers of strands 100 of sixty-four yield E-glass at a density offour strands per inch, and four layers of E-glass mat 102, in theisophthalic polyester resin 120. It should be noted that as understoodby one of ordinary skill in the art, the layers of the column section 52may be “stacked” in a different direction than the layers in thebaseplate 30; for instance, the layers in the baseplate may be stacked“north-south” and the layers in the column section 52 may be stacked“east-west.” The cap sections 54 may be an alternating layeredconstruction having four layers of strands 100 of sixty-four yieldE-glass at a density of eight strands per inch, and five layers ofE-glass mat 102, in the isophthalic polyester resin 120. The top plate80 may likewise be four feet by fifty feet by ½ inch thick and made inan alternating layered fashion with four layers of strands 110 ofsixty-four yield E-glass at a density of six strands per inch, and fivelayers of E-glass mat 112, both in an isophthalic polyester resin 120.The top plate 80 may be secured to the baseplate by ½ inch diameterbolts at two inch spacings. Both the baseplate 30 and the top plate 80may be made using a pultrusion process. Such an arrangement should besuitable for supporting a HS-25 loading as defined by the AmericanAssociation of State Highway and Transportation Officials (AASHTO).

The description of the structural assembly 20 given above has assumedthat the baseplate 30 is disposed beneath the top plate 80; however, therelative positions of the two components may be switched withoutdeparting from the scope of the present invention. For example, while itmay be less advantageous, the top plate 80 may be disposed below thebaseplate 30, with the ribs 50 extending downwardly. As such, the terms“baseplate” and “top plate” are not intended to be interpreted asimplying relative locations, and are not intended to exclude suchinverted arrangements.

The generic term “strands” have been used to describe the grouping ofreinforcing fibers (filaments) indicated at 100, 110. It should be notedthat this generic term is intended to encompass what are alternativelyknown in the industry as “ends,” “tows,” “rovings,” and the like. Suchstrands may be made from glass fibers (e.g., S-glass, E-glass), aramidfibers, carbon fibers, graphite, and the like.

While the invention has been illustrated and described in detail in thedrawings and foregoing description, the same is to be considered asillustrative and not restrictive in character, it being understood thatonly some embodiments have been shown and described and that all changesand modifications that come within the meaning and equivalency range ofthe appended claims are intended to be embraced therein.

1. A structural assembly, comprising: a baseplate formed from a firstcomposite matrix comprising reinforcing fibers in a polymer resin, saidbaseplate comprising: a generally planar base section having a firstside corresponding to a first of upper and lower faces thereof and asecond side corresponding to another of said of upper and lower faces; aplurality of ribs extending from said first side of said base section; aplurality of open channels disposed between said ribs and generallybounded by adjacent said ribs and said first side of said base section;and a top plate formed from a second composite matrix of reinforcingfibers in a polymer resin, said top plate secured to said baseplate soas to generally enclose said channels for at least a portion thereof;wherein said baseplate is generally horizontally disposed; wherein saidribs extend from said first side of said base section generallyperpendicular thereto in an extension direction and spaced from a centerof said base section in a direction generally transverse to saidextension direction; said ribs comprising laterally extending capsections disposed distal from and generally parallel to said first sideof said base section; wherein said open channels are laterally definedby said ribs of the same baseplate; wherein said first composite matrixincludes a plurality of first strands of reinforcing fibers, said firststrands oriented in a first direction generally parallel to saidchannels; wherein said second composite matrix includes a plurality ofsecond strands of reinforcing fibers, said second strands orientedgenerally perpendicular to said first strands; and wherein said topplate is removably secured to said baseplate.
 2. The assembly of claim 1wherein said ribs are regularly spaced from one another.
 3. The assemblyof claim 1 wherein said baseplate has a width transverse to said ribs offour feet or more.
 4. The assembly of claim 1 wherein said top plate issecured directly to said ribs.
 5. The assembly of claim 1 wherein saidfirst composite matrix further comprises a plurality of layers of mattedreinforcing fibers having a random orientation.
 6. The assembly of claim5 wherein substantially all reinforcing fibers in said first compositematrix are either said strands oriented in said first direction or saidmatted reinforcing fibers having a random orientation.
 7. The assemblyof claim 1 wherein said plurality of open channels includes at least acentral channel running along a center of said base section.
 8. Theassembly of claim 1 wherein said baseplate is disposed below said topplate.
 9. The assembly of claim 1 wherein said top plate, when attachedto said baseplate, encloses said channels along substantially all thelength thereof.
 10. The assembly of claim 1 wherein the matrix of atleast one of said base section and said top plate is non-opaque.
 11. Theassembly of claim 1 wherein said baseplate is a first baseplate, whereinsaid channels are first channels, and further comprising a secondbaseplate substantially similar to said first baseplate and havingsecond channels, wherein said top plate secures to said first and secondbaseplates so as to generally enclose at least a portion of both saidfirst channels and said second channels.
 12. A method of forming acomposite structural assembly, comprising: forming a baseplate from afirst composite matrix comprising reinforcing fibers in a polymer resinvia a pultrusion process, said baseplate comprising: a generally planarbase section having a first side corresponding to a first of upper andlower faces thereof and a second side corresponding to another of saidof upper and lower faces; a plurality of ribs extending from said firstside of said base section; a plurality of open channels disposed betweensaid ribs and generally bounded by adjacent said ribs and said firstside of said base section; and forming a top plate from a secondcomposite matrix of reinforcing fibers in a polymer resin; thereafter,securing said top plate to said baseplate so as to generally enclose atleast a portion of said channels; wherein said ribs extend from saidfirst side of said base section generally perpendicular thereto; whereinsaid ribs comprise laterally extending cap sections disposed distal fromand generally parallel to said first side of said base section; whereinsaid baseplate is generally horizontally disposed; wherein said firstcomposite matrix includes a plurality of first strands of reinforcingfibers; wherein said second composite matrix includes a plurality ofsecond strands of reinforcing fibers; wherein said top plate isremovably secured to said baseplate, and further comprising: orientingsaid first strands in a first direction generally parallel to saidchannels during said pultrusion; orienting said second strands in asecond direction; and wherein said securing said top plate to saidbaseplate comprises securing said top plate to said baseplate such thatsaid second direction is generally perpendicular to said first directionof said first strands.
 13. The method of claim 12 wherein forming saidtop plate from a second composite matrix comprises forming said topplate with at least one portion thereof being non-opaque.
 14. The methodof claim 12 wherein said ribs are regularly spaced from one another. 15.The method of claim 12 wherein said ribs have a generally T-shapedcross-section.
 16. The method of claim 12 wherein said ribs extend fromsaid first side of said base section generally perpendicular thereto.17. The method of claim 12 further comprising generating light with atleast one of said channels, said light being visible through said basesection.
 18. The method of claim 12 wherein said baseplate is disposedbelow said top plate.
 19. The method of claim 12 wherein forming saidbaseplate from a first composite matrix comprises forming said baseplatewith at least one portion thereof being non-opaque.
 20. The method ofclaim 12 wherein said baseplate is a first baseplate, wherein saidchannels are first channels, and further comprising forming a secondbaseplate substantially similar to said first baseplate and havingsecond channels, and further comprising said securing said top plate tosaid first and second baseplates so as to generally enclose at least aportion of said first and second channels.